A popular type of lamp, used on desks, work tables, drawing boards, for medical examinations and the like, utilizes a bracket having a principal arm mounted on a fulcrum, and an extensible forward arm hinged to the principal arm. One form of extensible lamp bracket is both counter-balanced and tiltable out of a central vertical plane; this form is disclosed in U.S. Pat. No. 3,391,890. The mechanism there shown contains provisions which permit three degrees of angular movement about the balance point, as with a ball joint. These provisions occupied the balance point itself so that electrical connectors could not be internal, and the fulcrum hinge presented a similar wiring problem.
In this type of lamp bracket, balancing at various degrees of extension was achieved by maintaining maintained proportionality between the extension of the forward arm forwardly of the balance point, and aft movement of the counter-balance. Proportionality was achieved by a rod which in effect maintains the forward arm parallel to a link from the balance point to the fulcrum hinge of the principal arm. In the patented construction, the fulcrum hinge was spaced below the principal arm; the parallelism-maintaining rod was spaced still further below. This separation interfered with compact folding of the bracket.